# US 5,348,025 A · Apparatus and method for measuring mobility of the scaphoid > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,348,025 A - Document ID: US5348025A - Status: Granted - Kind: A - Application number: 08/020,773 - Filed: 1993-02-22 - Granted: 1994-09-20 - Earliest claimed: 1993-02-22 - Assignees: Yale University - Inventors: Scott W. Wolfe; Joseph J. Crisco - Web page: https://patentgrep.com/patent/US5348025A ## CPC - A61B 5/4528: {Joints (A61B5/4533, A61B5/4538 take precedence)} - A61B 5/1107: {Measuring contraction of parts of the body, e.g. organ or muscle} - A61B 5/6824: {Arm or wrist} - A61B 5/6825: {Hand} - A61B 5/70: {Means for positioning the patient in relation to the detecting, measuring or recording means} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract An apparatus and method for measuring mobility of a subject's scaphoid. The apparatus includes a force applicator that applies a variable force to the scaphoid, a load cell that generates a first signal corresponding to the magnitude of the force, and a displacement sensor that generates a second signal corresponding to a displacement of the scaphoid in response to the applied variable force. ## Claims ### Claim 1 Apparatus for measuring mobility of a free-floating bone in a subject's wrist, said apparatus comprising: a support structure designed to support the subject's hand and to permit unobstructed movement of the free-floating bone when supporting the subject's hand, a force applicator positioned over and applying a variable force to said free-floating bone while the subject's hand is being supported by the support structure, a load cell generating a first signal corresponding to the magnitude of said variable force, and a displacement sensor generating a second signal corresponding to a displacement of said free-floating bone in response to said variable force. ### Claim 2 (depends on 1) The apparatus of claim 1 wherein said free-floating wrist bone is the scaphoid. ### Claim 3 (depends on 2) The apparatus of claim 2 wherein said force applicator comprises a plunger assembly by which a user can manually apply a force to the subject's scaphoid. ### Claim 4 (depends on 3) The apparatus of claim 3 wherein said plunger assembly comprises a handle, a rod and a bearing assembly guiding said rod. ### Claim 5 (depends on 4) The apparatus of claim 4 wherein said load cell is located between said handle and said rod. ### Claim 6 (depends on 1) The apparatus of claim 1 wherein said force applicator includes an end piece having a concave region which contacts the subject's hand. ### Claim 7 (depends on 6) The apparatus of claim 6 wherein said end piece is a cap fitting over the end of said rod. ### Claim 8 (depends on 1) The apparatus of claim 1 wherein said force applicator comprises a plunger assembly by which a user can manually apply a force to the subject's scaphoid and wherein said apparatus further comprises a rigid member coupling said displacement sensor to the plunger assembly. ### Claim 9 (depends on 2) The apparatus of claim 2 further comprising a display device displaying said second signal as a function of said first signal for a range of forces applied to the subject's scaphoid. ### Claim 10 (depends on 11) The apparatus of claim 11 wherein said display device comprises a video screen. ### Claim 11 (depends on 2) The apparatus of claim 2 further comprising a support structure for supporting the subject's hand in a position so as to perform scaphoid mobility measurements. ### Claim 12 (depends on 11) The apparatus of claim 11 wherein said support structure comprises an arm rest. ### Claim 13 (depends on 12) The apparatus of claim 12 wherein said arm rest includes an arm restraint for securing the subject's forearm to the arm rest. ### Claim 14 (depends on 13) The apparatus of claim 13 wherein said arm restraint comprises velcro straps. ### Claim 15 (depends on 11) The apparatus of claim 11 wherein said support structure further comprises a hand support for supporting the subject's hand. ### Claim 16 (depends on 15) The apparatus of claim 15 wherein said hand support further comprises a restraint securing the subject's hand to the hand support. ### Claim 17 (depends on 16) The apparatus of claim 16 wherein said hand restraint comprises velcro straps. ### Claim 18 Method for measuring mobility of a free-floating bone in a subject's wrist, said method comprising the steps of: applying a variable force to said free-floating bone, measuring said variable force, measuring displacements of said free-floating bone in response to said force, and displaying the displacement of said free-floating bone versus the measured variable force. ### Claim 19 (depends on 18) The method of claim 18 wherein said free-floating wrist bone is the scaphoid. ### Claim 20 (depends on 19) The method of claim 19 further comprising supporting the subject's hand during the step of applying the variable force to said free-floating bone, wherein the step of supporting the subject's hand is done in such a manner that movement of the free-floating bone is unobstructed. ### Claim 21 (depends on 20) The method of claim 20 wherein the step of supporting the subject's hand further comprises restraining the subject's hand during the force applying step.